池养河蟹性早熟现象的初步分析

应用正交试验法研究了积温、营养、品系３个因素对河蟹性早熟的影响。通过观察蟹种外部形态特征和内部性腺发育情况确定性早熟比例，从而得出初步结论：不同品系河蟹性早熟比例有显著差异（Ｆ〉０．０５），认为遗传因素是导致性早熟产生的主要原因。同时提出了用第２步足跗节内侧刚毛多寡来判别雄性蟹种的性早熟，即当跗节近趾节端１／３处密布刚毛、长度２ｍｍ左右时，即已成熟，此时性腺成熟系数０．８以上。

Preliminary analysis on precocious phenomenon of mitten crab, Eriocheir sinensis reared in ponds

Effects of different accumulative temperature, nutrition and strain on preconciousness of mitten crab \%Eriocheir sinensis\% were studied by using the orthogonal design method. Extra morphological characters and internal sexual gland development of mitten crab indicate the proportion of precocious mitten crab. It was found that precocious proportion was different among different strains of mitten crab, that is, hereditary factor is the chief cause of preconciousness. A way to discriminate preconciousness of male crabs was developed by inner side seta of second ambulatary leg, when the animals reach about 2.0 mm length. When mitten crab mature, gonadosomatic index will be over 0.8%.